Vehicle operators are often exposed to intense light sources that can temporarily blind them while driving. Such light sources can include the sun during the day and oncoming headlights at night, for example. In addition, fixed sources of bright light, such as misdirected lighting at a factory and the like can also blind a driver. These intense light sources are a safety hazard by posing a distraction while driving. For example, the intense light may prevent drivers from seeing a possible hazard in their path. Moreover, an intense light will probably require drivers to adjust their sun visor to block the light source, which reduces their attention to their driving. Further, the sun visor itself will obstruct or lower a driver's visibility. In addition, there are many times when the sun visor, due to its mechanical limitations, is ineffective in blocking light when the light source is in areas not covered by the visor.
One solution is to provide tinting of the windshield and other glass of the vehicle. However, complete tinting of a windshield is illegal, and is also impractical at night. Moreover, the amount of tinting is limited by law, and therefore cannot provide sufficient protection from intense light sources such as the sun.
Another solution is to provide filtering, such as the use of a liquid crystal display (LCD) screen which can be used with cameras and sensors to detect the existence and position of a light source. This, along with the visual detection of a driver in the vehicle, is used to determine which portions of the LCD can be activated to block the driver's eyes from the light source. However, this solution has the disadvantage of being expensive, in that extra sensor and camera hardware is needed to not only detect the driver's (eye) position but also the light source position. Moreover, the system requires extensive computational complexity to track not only the driver position but also the light source position, and then to calculate their geometry in relation to the filter and the coordinates of the specific pixels of the filter to activate in order to block the light from the source to the driver.
Another solution is to provide spectacles that can block light. This solution has the same hardware problems of the previous case, and also requires even better tracking algorithms as the system must account for the movement of a driver's head. As a result, this system must track the light source, driver, and spectacles, making the real-time computational requirements even more severe. In addition, the wearing of these cumbersome spectacles would be a burden on the driver, making this solution impractical.
Another solution is to provide an automated mechanical visor system. However, not only does this system have the same problems as the sun visor described above, it also has the disadvantage of extreme hardware additions and modifications, not to mention the extensive control logic requirements. In addition, this system is prone to blockage of movement and mechanical breakdown.
Therefore, the need exists for a system and method to selective attenuate intense light sources that do not require additional sensors and cameras, and do not require the tracking of a driver's eyes or position. It would also be of benefit to provide such a system and method with a minimum amount of vehicle modifications, in order to reduce complexity, increase reliability and lower costs.